1. Field of the Invention
The present invention relates to an improvement in a shaft seal quenching mechanism used with an airtightly sealed liquid containing much slurry.
2. Prior Art
A slurry seal, as typically shown in FIG. 3, has so far been provided as a shaft seal means to a slurry pump used for pumping up muddy water and other purposes.
As illustrated, the slurry seal comprises a fixed seal ring 103 tightly fitted through a packing 102 into a flange 101 located on the side of a pump casing and a rotary seal ring 108 tightly fitted through a packing 107 into a seal cover 106 secured to a sleeve 105 of a shaft 104. Both the seal rings 103 and 108 slide closely on their respective sliding faces 103a and 108a, thereby preventing a liquid sealed in a sealing space S, which leads to an impeller (not shown), from leaking from around the shaft 104.
When the liquid confined in the sealing space S contains a large amount of slurries of earth and sand or coal dust, neither self-lubrication of the sliding faces 103a and 108a nor self-cooling of both the seal rings 103 and 108 is possible. In this case, a quenching mechanism is conventionally added to the slurry seal for auxiliary lubricating and cooling purposes.
As illustrated in FIG. 3, the quenching mechanism comprises a quenching hole 109 which is open on the side of the packing 102--located between the fixed seal ring 103 and the flange 101--opposite to the sealing space S and a baffle sleeve 110 located between both the fixed seal rings 103, 108 and the sleeve 105 of the shaft 104 and having its one end fixed to an internal end of the flange 101 and its other end extending to the rear end of the rotary seal ring 108. Quenching water fed through the quenching hole 109 to the side 113 of the packing 102 opposite to the sealing space S flows through a path 111 between the baffle sleeve 110 and the seal rings 103, 108 toward the seal cover 106, whence it is discharged through a path 112 between the baffle sleeve 110 and the sleeve 105 to the atmosphere A.
A problem with the above-mentioned conventional quenching mechanism, however, is that the quenching water is discharged into the path 112 before effective cooling is achieved, since it does nothing but to flow through the path 111 along the baffle sleeve 110.
In view of the foregoing, the present invention seeks to provide a quenching mechanism which allows quenching water to be distributed throughout gaps on the side of the fixed seal ring opposite to the sealing space.